1. Technical Field
The disclosure relates to a contact detecting apparatus for detecting contact between a body tissue and a measurement probe for emitting illumination light onto a body tissue in contact with a distal end thereof and receiving return light of the illumination light scattered from the body tissue, and to an optical measurement apparatus having the contact detecting apparatus for calculating a specific value representing characteristics of the body tissue, and to a contact detecting method.
2. Related Art
In the past, an optical measurement apparatus is known, which emits illumination light onto a body tissue, and calculates a characteristic value representing characteristics of the body tissue on the basis of a measured value of return light (scattered light) scattered from the body tissue. The optical measurement apparatus is used in combination with an endoscope for observing organs such as a digestive system. As such optical measurement apparatus, an optical measurement apparatus has been proposed, which uses LEBS (Low-Coherence Enhanced Backscattering) for detecting characteristics of a body tissue by emitting white light of low coherence of which spatial coherence length is short onto a body tissue from an illumination fiber distal end of a probe, and by using multiple light-receiving fibers to measure the intensity distribution of the return light at multiple angles (see United States Patent Application Publication No. 2010/0053632).